Project Summary TB remains one of the leading causes of death from infectious disease worldwide, and treatment adherence a persistent challenge. This is particularly pressing in high-burden, low- resource settings such as Cambodia, where approximately two-thirds of people carry the TB bacterium, one of the highest rates in the world. We propose to develop and pilot a novel smartphone-based intervention to improve TB treatment adherence, integrating video-enabled Directly Observed Therapy (VDOT) with transfers of mobile money and phone ownership to compliant patients. This intervention aims to directly address two of the key barriers to TB treatment adherence in low resource settings where DOT is costly or impractical. First, the video component has the potential to substitute direct in-person observation with time-stamped videos of patients taking their medication. Second, our proposed intervention incorporates incentives to patients for treatment adherence and equipment preservation in the form of mobile money and eventual phone ownership upon treatment completion. In partnership with the National Tuberculosis Program (NTP), we will assess the feasibility of this intervention and of a future randomized study in two districts of Cambodia. First, we will extend and adapt an existing platform for video-enabled medication monitoring (Mobile Interactive Supervised Therapy (MIST)) to incorporate mobile cash payments conditional upon compliance. We then identify and address outstanding technical and usability issues with the platform by conducting an initial 1-month test of the intervention with 10 TB patients. Finally, we conduct a 6-month demonstration study among 50 households in our study locations to assess the acceptability, implementation, and potential for scale up of the intervention. We also aim to assess the practicalities and challenges of a future randomized controlled effectiveness and cost-effectiveness trial. To the best of our knowledge, this study is the first to examine a mHealth intervention for TB that integrates both adherence monitoring and patient incentives into a single platform. The results will be of immediate relevance to the NTP as well as other TB control programs seeking new alternatives to improving adherence, especially where traditional DOT may be infeasible or costly. These results will also be of interest outside the area of TB where adherence to treatment is critical, such as HIV. More generally, the study will provide key insights into mHealth programs in a setting relevant to other developing countries. This project will involve building new capacity in Cambodia for behavioral research, mHealth, and communications through training to the study personnel and general training on conducting TB and/or mHealth research to study partners and other stakeholders in the country.